Dialuminium nickel tetraoxide

Endpoint summary

Description of key information

Two in vitro tests were performed in order to assess the irritation potential of nickel aluminate: In the performed in vitro tests, the test substance nickel aluminate did neither have skin irritation nor eye irritation potential.
Read-across from nickel oxide:
The results of two guideline-based, GLP studies recently conducted by Eurofins Product Safety Laboratory (EPSL) evaluating eye and skin irritation potential indicate that the compound is only slightly or mildly irritating.  The results for eye and skin irritation do not meet the classification criteria for either endpoint.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

In vitro test: skin irritation

The skin irritation potential of nickel aluminate was tested according to the draft OECD guideline "In vitro skin irritation: human skin model test", dated December 2007 (Heppenheimer, 2009). The administration of 15 mg of the test substance to the human skin model EpiDerm^TM did not cause effects, e. g. loss of viability, suggesting irritation potential.

In vitro test: eye irritation

The in vitro HET-CAM test following the ICCVAM test method (dated November 2006) was performed to evaluate the irritation potential of nickel aluminate (Paulus, 2009). The application of 300 µL of the test substance on the chorioallantoic membrane (CAM) of incubated chicken eggs did not cause effects related to irritation, e. g. haemorrhage, lysis or coagulation, on the CAM.

There are no in vivo skin or eye irritation data available for nickel aluminate. However, there are reliable data available for the structurally related substance nickel oxide. Thus, read-across was conducted based on an analogue-approach.

Information characterizing the potential for nickel oxide to cause irritation/corrosion generally indicates that the compound is only slightly irritating. This indication is based on the results of two guideline-based, GLP studies recently conducted by Eurofins Product Safety Laboratory (EPSL) evaluating eye and skin irritation potential.

The skin irritation study was conducted in rabbits according to OECD Test #404 - Acute Dermal Irritation/Corrosion guidelines. Three healthy female rabbits were exposed via the skin to green nickel oxide to determine if the test substance had the potential to produce irritation. Erythema was noted in all test animals at the 30-60 minute time point (each animal was scored as 1), but not at the remaining time intervals (scored as 0). No edema was observed during the study (each animal scored as 0 at all time points). The overall incidence and severity decreased with time, and the effects were fully reversible within 24 hours. According to OECD Test #404 guidelines, compounds should be considered an irritant if responses persist to the end of the observation period; however, findings of this study indicated effects were fully reversible significantly prior to the end of the observation period.

The eye irritation study was also conducted in rabbits according to OECD Test #405 -Acute Eye Irritation/Corrosion guidelines. In this study, green nickel oxide was instilled into the right eye of three healthy female rabbits to determine the potential to produce irritation. In the treated eyes, no corneal opacity or iritis was observed in any of the animals, though all three treated eyes exhibited positive conjunctivitis one hour after instillation. All observed effects were reversible; incidence and severity of irritation decreased with time and all animals were free of ocular irritation by Day 4. Aside from eye irritation, no other signs of gross toxicity, adverse pharmacologic effects, or abnormal behavior were observed in the animals. The results of the study indicated that nickel monoxide was mildly irritating to the eye under the conditions of the study. The OECD Test #405 guidelines state that extrapolation of these results to humans is only valid to a limited degree as in many cases the albino rabbit is more sensitive than humans to ocular irritants for corrosives.

Collectively, these two studies provide reliable, adequate information to assess the irritant/corrosive properties of green nickel oxide. The studies were specifically designed to evaluate the health hazard likely to arise from exposure by dermal or ocular application. Results demonstrated that green nickel oxide can cause minor irritation in laboratory settings. However, all observed effects were fully reversible and generally classified as “slight” or “mild,” thus indicating a limited potential for irritant/corrosive potential.

Justification for classification or non-classification

In vitro test: skin irritation

There is conclusive data available which is not sufficient for classification.

In vitro test: eye irritation

There is conclusive data available which is not sufficient for classification.

Based on the read-across from the structurally related substance, it is predicted that nickel aluminate is not irritating to the skin and the eye in vivo.